1. Field of the Invention
The subject invention relates to television receivers having the capability of displaying Picture-In-Picture (PIP).
2. Description of the Related Art
PIP is a feature in a television receiver in which the picture from a video signal in a main channel fills the display, while the picture from a video signal in an auxiliary channel is sub-sampled and overlays a portion of the main picture on the display. This enables a user of the television receiver to monitor the video signal from an alternate source, e.g., a television channel from a second tuner, the signal from a video cassette recorder or a video camera, etc.
However, when displaying the PIP signal, a portion of the main picture is lost. Depending on the content of the main picture, the area occupied by the PIP picture may obscure an important portion of the main picture, for example, in sports, this important portion may be that devoted to displaying the current score, while in a movie, this portion may be that devoted to displaying the faces of the leading characters.
In order to alleviate this problem, it is known to be able to move the PIP picture to various different positions under control of the user, to reposition the PIP picture such that it does not obscure an important information of the main picture.
U.S. Pat. No. 6,008,860 discloses circuitry with which the size of the PIP picture may be selectively reduced to further obscure less of the main picture.
In each of the above arrangements, it is up to the user to determine when such important information is being obscured and to take the corrective action, i.e., reducing the size of the PIP picture or moving the PIP picture, or both.
It is an object of the present invention to provide a television receiver having a PIP capability in which the size and position of the PIP picture are adjusted automatically in dependence on the content of the main picture.
The above object is achieved in a television receiver having a picture-in-picture (PIP) functionality, said television receiver comprising a main video path including an input for receiving a main video signal, and a main signal video processing circuit for processing the main video signal in the main video path; an auxiliary video path including an auxiliary input for receiving an auxiliary video signal, and an auxiliary signal video processing circuit for sub-sampling and processing the auxiliary video signal in the auxiliary video path; a display for displaying video signals; and means for selectively applying processed main video signal and the sub-sampled auxiliary video signal to the display such that a picture from the sub-sampled auxiliary video signal overlies a portion of a picture from the main video signal, wherein said selectively applying means comprises means for detecting and analyzing characteristics of the main video signal; and means for changing attributes of the PIP picture in response to said detected and analyzed characteristics of the first video signal.
Applicants have determined that by analyzing the main video signal, regions in the picture frame may be found which contain relatively unimportant information. These regions may be identified by examining motion and texture, wherein regions having relatively no motion, the least texture, i.e., having a single color, or having a repeated texture, may be candidates for the positioning of the PIP image. Based on the size and positioning of these candidate regions, the size and positioning of the PIP image may be changed to coincide with that of one of the candidate regions.